Remittances economy,remittances landscape: an analysis of the economic and socioecological implications of remittances to households in South Eastern Nigeria     

Nnamdi Ifeanyi Maduekwe  Francis Adesina 《GeoJournal》2017,82(1):139-155

This study evaluated the level of household dependence on remittances, its uses and linkages with landscape/environmental conditions in South Eastern Nigeria. The study area is a landscape unit defined by the Idemili River Basin of Anambra State. The concept of socio-ecological systems provided the basis for an integrated assessment of remittances environment linkages using primary data from a survey of 840 households in 25 localities in the basin and landscape data from a Nigerias at 32 m resolution image dataset. Based on this, linear and non linear regression modelling of locality level relationships between four indicators of household remittances (HR) and a key landscape variable (vegetation cover density-VCD) was implemented. About 45 % of the households had access to remittances; 10 % of receiving households depended on it as their main income source; and over 87 % used the receipts mainly to meet basic household needs. Only 4 % of the households used it in activities that directly affected the vegetation cover. The linear and non linear relationships between the indicators of HR and VCD were generally weak (R² < 0.250). However, the pattern of relationship was different for various indicators of HR. It was inverse for locality aggregate (total) and average HR and positive for level of household access to remittances/locality. This illustrates the complex relationship between remittances and landscape variables in the basin. The study shows that the impact of remittances on households and the environment in the region is both positive (through the alleviation of poverty and land pressure) and negative (through reduction of vegetation cover density).  相似文献   

Assessment of heavy metals in soil and terrestrial isopod <Emphasis Type="Italic">Porcellio laevis</Emphasis> in Tunisian industrialized areas     

Chedliya Ghemari  Christophe Waterlot  Anas Ayari  Julie Leclercq  Francis Douay  Karima Nasri-Ammar 《Environmental Earth Sciences》2017,76(17):623

In this study, data on several metals (Cd, Pb, Zn and Cu) in soil and isopod Porcellio laevis taken at 21 sites from the most important industrial areas in Tunisia (Bizerte, Nabeul, Zaghouan, Sfax and Gabes) were presented. Heavy metal concentrations in both soil samples and isopods were determined using atomic absorption spectrometry. Soil contamination was estimated using the contamination factor (CF). On the other hand, the bioaccumulation factor (BAF) was determined to estimate metal accumulation in isopods. The CF values show that the level of contamination varies between sampled soils, which may be due to the source of pollution at each site. The BAF values allow defining the order of accumulation in P. laevis which was classified for the majority of the sampled sites as a macro-concentrator of Cu and Zn and a deconcentrator of Cd with some exceptions. A principal component analysis (PCA) was conducted between soil properties (pH, OM and CaCO₃) and metal concentrations in soils. Through PCA, we obtained four groups in which soils were distinguished by their physicochemical properties and their metal concentrations. Moreover, linear multiple regressions with a downward stepwise procedure were conducted to test the relationships between the physicochemical parameters and metal concentrations in both soils and isopods. Thus, positive correlations (0.78 < R ² < 0.99) were obtained for Pb considering dataset from the groups 1, 2 and for Zn with data of groups 2 and 3. Finally, results showed that P. laevis could be used as a bio-indicator for monitoring and reducing the impact of pollution in terrestrial ecosystems.  相似文献   

Temporospatial dynamics and public health significance of bacterial flora identified on a major leatherback turtle (Dermochelys coriacea) nesting beach in the Southern Caribbean          下载免费PDF全文

Ayanna Carla N. Phillips  Johanna Coutou  Stacy Rajh  Neville Stewart  Antonio Watson  Adam Jehu  Hamish Asmath  Francis Dziva  Chandrashekhar Unakal  Ridley Holder  Raymond Raoul Carthy 《Marine Ecology》2017,38(2)

Grande Riviere beach, on the island of Trinidad, supports the largest nesting population of leatherback turtles in the Caribbean region. Throughout the nesting season, nests are naturally disturbed by newly nesting females, resulting in egg breakage and loss of some nest viability. This environment is ideal for the growth and proliferation of microorganisms. The range of bacterial flora present in beach sand and egg shells was examined, with emphasis on bacteria that may pose a threat to public and animal health. The extent to which the bacterial load and genera on the beach changed throughout the season was also assessed. Twenty‐five genera were identified, with Pseudomonas spp. found to be the most predominant environmental bacteria. Four genera identified possess zoonotic potential, while five additional genera are known to be of public and animal health significance. Distinct shifts in the density and distribution of bacteria were observed along the beach from early to peak nesting season. Shifts were seen across heavily traversed zones, thus highlighting the potential exposure threats posed to beach visitors and animals alike. Further studies aimed at speciating this population of bacteria, as well as isolating potential fungal pathogens may mitigate this threat. Identification of bacterial agents that are specifically pathogenic to leatherback turtles, turtle eggs, hatchlings and those who may interact with these animals will serve to enhance and guide efforts to better conserve this species and protect the health of all who visit this ecologically significant site.  相似文献   

Responses of coastal lagoon plant communities to levels of nutrient enrichment: A mesocosm study   总被引：1，自引：0，他引：1  

D. I. Taylor  S. W. Nixon  S. L. Granger  B. A. Buckley 《Estuaries and Coasts》1999,22(4):1041-1056

An experiment was conducted to quantify the effects of different levels of nutrient enrichment on the plant communities of temperate coastal lagoons, specifically the lagoons of the northeast U.S. Ten mesocosms, each containing coastal water, lagoon sediments, and plants and animals found in natural lagoons, were subjected to five levels of enrichment. Two mesocosms served as controls, and received no experimental nutrient additions. The remaining 8 mesocosms were enriched in duplicate with ammonium plus phosphate at 1.0 and 0.11 mmol N or P m^?2 d^?1, 2.0 and 0.19 mmol N or P m^?2 d^?1, 4.0 and 0.35 mmol N or P m^?2 d^?1, and 8.0 and 0.67 N or P mmol m^?2 d^?1. At all levels of enrichment, and through much of the experiment, water column concentrations of dissolved inorganic nitrogen (DIN) were drawn down to background levels. Despite the efficient drawdown of added DIN even at the highest loadings, differences in plant biomass among the 5 treatments were difficult to detect. Enrichment at the highest loadings increased standing stocks of phytoplankton for one month mid-experiment. No significant effect of loading could be detected for dry biomass of eelgrass (Zostera marina), epiphytic material, drift macroalgae, or for all plant components combined. The experiment has demonstrated that the enrichment responses of coastal lagoons can be diverse, especially at intermediate loadings.  相似文献   

Marine and estuarine shallow water science and management: The interrelationship among habitats and their management     

Francis J. Reill  Ralph J. Spagnolo  Edward Ambrogio 《Estuaries and Coasts》1999,22(3):731-734

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Early Optical Observations of Gamma-Ray Bursts Compared with Their Gamma- and X-Ray Characteristics Using a MASTER Global Network of Robotic Telescopes from Lomonosov Moscow State University     

O. A. Ershova  V. M. Lipunov  E. S. Gorbovskoy  N. V. Tyurina  V. G. Kornilov  D. S. Zimnukhov  A. Gabovich  O. A. Gress  N. M. Budnev  V. V. Yurkov  V. V. Vladimirov  A. S. Kuznetsov  P. V. Balanutsa  R. Rebolo  M. Serra-Ricart  D. Buckley  R. Podesta  H. Levato  C. Lopez  F. Podesta  C. Francile  C. Mallamaci  S. A. Yazev  D. M. Vlasenko  A. Tlatov  V. Senik  V. Grinshpun  A. Chasovnikov  V. Topolev  A. Pozdnyakov  K. Zhirkov  D. Kuvshinov  F. Balakin 《Astronomy Reports》2020,64(2):126-158

We present the results of early observations for 130 error-boxes of gamma-ray bursts performed with the Mobile Astronomical System of TElescope-Robots (MASTER) global network of robotic telescopes from Moscow State University in fully automatic mode (2011–2017). Among them, GRB 130907A, GRB 120811C, GRB 110801A, GRB 120404A, GRB 140129B, GRB140311B, and GRB 160227A are considered in details. Among these 130 gamma-ray bursts, in the first 60 s after the trigger with the Swift, Fermi, INTEGRAL, MAXI, Lomonosov, and Konus-Wind orbital observatories, the MASTER was pointed on 51 gamma-ray bursts, being the leader in terms of the first pointing. Full observation automation and MASTER own real-time image processing software allowed us to obtain unique data on early optical emission that accompanied 44 gamma-ray bursts (GRB 110801A, GRB120106A, GRB 120404A, GRB 120811C, GRB 120907A, GRB 121011A, GRB 130122A, GRB 130907A, GRB 131030A, GRB 131125A, GRB 140103A, GRB 140108A, GRB 140129B, GRB 140206A, GRB 140304A, GRB 140311B, GRB 140512A, GRB 140629A, GRB 140801A, GRB140907A, GRB 140930B, GRB141028A, GRB 141225A, GRB 150210A, GRB 150211A, GRB 150301B, GRB 150323C, GRB 150404A/Fermi trigger 449861706, GRB 150403A, GRB 150413A, GRB 150518A, GRB 150627A, GRB 151021A, GRB 151215A, GRB 160104A, GRB 160117B, GRB 160131A, GRB 160227A, GRB 160425A, GRB 160611A, GRB 160625B, GRB 160804A, GRB 160910A, GRB 161017A, GRB 161117A, GRB 161119A). We obtain light curves for 13 gamma-ray bursts among the above listed ones and compare the data in the optical (MASTER), X-ray (Swift-XRT), and hard X-ray (Swift-BAT) ranges.  相似文献   

Connectivity as an emergent property of geomorphic systems     

Ellen Wohl  Gary Brierley  Daniel Cadol  Tom J. Coulthard  Tim Covino  Kirstie A. Fryirs  Gordon Grant  Robert G. Hilton  Stuart N. Lane  Francis J. Magilligan  Kimberly M. Meitzen  Paola Passalacqua  Ronald E. Poeppl  Sara L. Rathburn  Leonard S. Sklar 《地球表面变化过程与地形》2019,44(1):4-26

Connectivity describes the efficiency of material transfer between geomorphic system components such as hillslopes and rivers or longitudinal segments within a river network. Representations of geomorphic systems as networks should recognize that the compartments, links, and nodes exhibit connectivity at differing scales. The historical underpinnings of connectivity in geomorphology involve management of geomorphic systems and observations linking surface processes to landform dynamics. Current work in geomorphic connectivity emphasizes hydrological, sediment, or landscape connectivity. Signatures of connectivity can be detected using diverse indicators that vary from contemporary processes to stratigraphic records or a spatial metric such as sediment yield that encompasses geomorphic processes operating over diverse time and space scales. One approach to measuring connectivity is to determine the fundamental temporal and spatial scales for the phenomenon of interest and to make measurements at a sufficiently large multiple of the fundamental scales to capture reliably a representative sample. Another approach seeks to characterize how connectivity varies with scale, by applying the same metric over a wide range of scales or using statistical measures that characterize the frequency distributions of connectivity across scales. Identifying and measuring connectivity is useful in basic and applied geomorphic research and we explore the implications of connectivity for river management. Common themes and ideas that merit further research include; increased understanding of the importance of capturing landscape heterogeneity and connectivity patterns; the potential to use graph and network theory metrics in analyzing connectivity; the need to understand which metrics best represent the physical system and its connectivity pathways, and to apply these metrics to the validation of numerical models; and the need to recognize the importance of low levels of connectivity in some situations. We emphasize the value in evaluating boundaries between components of geomorphic systems as transition zones and examining the fluxes across them to understand landscape functioning. © 2018 John Wiley & Sons, Ltd.  相似文献   

Accretion of the NW Himalayan foreland pre-dates Late Cenozoic climate change     

Ellen A. Lamont  Francis J. Sousa  Andrew J. Meigs  Ramakrishna Jayangondaperumal  Rebecca M. Flowers  Aravind Anilkumar  Danielle Woodring  Edward R. Sobel 《地学学报》2023,35(1):41-48

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Dietary niche separation of three Late Pleistocene bear species from Vancouver Island,on the Pacific Northwest Coast of North America     

Cara Kubiak  Vaughan Grimes  Geert Van Biesen  Grant Keddie  Mike Buckley  Reba Macdonald  M. P. Richards 《第四纪科学杂志》2023,38(1):8-20

Competition between taxa related to climate changes has been proposed as a possible factor in Pleistocene megafaunal extinctions, and here we present isotope evidence of the diets of three co-existing bear species [black bear (Ursus americanus), brown bear (Ursus arctos), and the now extinct short-faced bear (Arctodus simus)] from a locale in western North America dating to the Late (Terminal) Pleistocene (~14.5–11.7 ka). The three bear species were found at several sites on Vancouver Island, on the western coast of Canada. To examine the chronological overlap and niche partitioning between these species of bear, we used direct radiocarbon dating, stable isotope analysis and ZooMS proteomic identification methods. Here we present new radiocarbon evidence from Terminal Pleistocene U. americanus, U. arctos and A. simus from several sites on the island, along with both bulk collagen and compound-specific isotope data for these species. Radiocarbon dates confirm the chronological overlap of Arctodus and both Ursus species in the montane regions of the island at the end of the Pleistocene. Stable isotope data reveal niche differentiation between these species, with U. americanus occupying a distinctly lower trophic position than the other two taxa.  相似文献   

Unusual electrical resistivity effects associated with fast-growing trees     

Brooks B. Ellwood  Francis B. Harrold 《Geoarchaeology》1993,8(2):157-162

A series of electrical resistivity profiles have been acquired in eucalyptus groves during archaeological surveys performed in Portugal. The combination of the sandy soils in the region plus the presence of high growth eucalyptus trees yielded anomalous resistivity values which were extremely high and showed large variability. Other moderate and low growth trees did not show similar unusual resistivities. We conclude that extreme caution must be exercised when interpreting data from archaeological surveys associated with unusual soils or vegetation. © 1993 John Wiley & Sons, Inc.  相似文献